Study Evaluates Effects of Probiotics for Horses

Furr described a preliminary study evaluating the effects of using Pediococcus acidilactici and Saccharomyces boulardii-based probiotics in horses.

Photo: The Horse Staff

Nutritional supplements containing probiotics are popular purchases for some horse owners, even if not all of these products' label claims are backed by research. But some researchers are working to better understand these probiotics' effects on horses. At the 2013 Western Veterinary Conference, held Feb. 17-21, in Las Vegas, Nev., one veterinarian presented research behind a certain type of probiotic supplement for horses.

Probiotics are a subtype of immunomodulators, which are substances designed to enhance the body’s defense mechanisms. Manufacturers market these nutritional supplements to support and protect the gastrointestinal (GI) system in a variety of mammals, including horses. Furr said that while probiotics’ mechanism of action remains “poorly described,” existing research suggests they can (when consumed appropriately) have a number of beneficial effects on animals’ immune system and/or GI tract function, including:

Stimulating immune responses through interaction with immune cells in the GI tract; or

Enhancing GI barrier function.

Furr said some scientists have suggested that, to be as effective as possible, the organisms in probiotics should be host-specific so they have a greater chance at surviving in and colonizing the gastrointestinal tract.

Scientists began exploring probiotic use in horses several years ago, Furr said; however, researchers are still working to understand which organisms are best suited for equine use. One study Furr cited evaluated the effects of Lactobacillus pentosus WE7 on foals with diarrhea; unfortunately, he said, the product actually appeared to increase the incidence and severity of the foals' diarrhea.

Another study evaluated two probiotic pastes containing "various combinations" of L. acidophilus, L. faecium, L. casei, L. plantarum, and Streptococcus faecium; neither paste had any effect on salmonella shedding in horses admitted to an equine hospital for colic, he said.

Moving forward, Furr said scientists have investigated P. acidilactici and S. boulardii use as probiotics in other species and have achieved favorable results. P. acidilactici is a fermentative bacterium known to colonize many species' digestive tracts. S. boulardii, a nonpathogenic type of yeast, has been used to treat diarrhea in humans for many years, he said.

Researchers have also studied P. acidilactici and S. boulardii in horses, although not extensively. In one study of horses with naturally occurring diarrhea, Furr said, S. boulardii appeared to reduce the median number of days the horse had diarrhea from seven to five. And Furr said researchers performing a preliminary clinical study of a small number of horses reported nonspecific health effects, including improved fecal consistency.

Armed with this information, Furr and colleagues decided to test the effects of P. acidilactici and S. boulardii on equine immune function parameters. Furr said their in vitro (in the lab) results demonstrated that a particular type of white blood cell found in horses responded to the probiotic organisms’ secretion products.

Next, Furr said, the team employed 12 horses to test the same probiotic combination in vivo (in the live horse) for 72 days. He said that he and colleagues “observed effects on some specific factors of immune function response. Understanding in which clinical conditions these effects might be most useful is the next important step.”

Furr said he and colleagues are trying to put together additional studies and are specifically interested in examining the organisms’ effects on parasite clearance. In the meantime, however, he offered some advice for owners: “In general, it appears that the available probiotic compounds are safe and unlikely to cause any problems; however, it remains unclear how useful they are overall. Further, the term ‘probiotic’ is very general, and there is likely to be a lot of difference between various products which use different organisms.

“Probiotics are not replacements for vaccinations, antibiotics, and dewormers when appropriate, or good veterinary advice,” Furr stressed.

About the Author

Erica Larson, news editor, holds a degree in journalism with an external specialty in equine science from Michigan State University in East Lansing. A Massachusetts native, she grew up in the saddle and has dabbled in a variety of disciplines including foxhunting, saddle seat, and mounted games. Currently, Erica competes in eventing with her OTTB, Dorado.

Stay on top of the most recent Horse Health news with FREE weekly newsletters from TheHorse.com. Learn More

Article

Article

Article

Article

POLL: Older Horse Care Concerns

What is your biggest concern for your older horse? Please explain in the comments below!

Maintaining weightOsteoarthritis and other lamenessDiseases such as PPID, EMS, and insulin resistanceKeeping them active and movingOther (please specify)I do not own an older horseComments. 100 Characters Max

Featured Adoptable Horse

Fury

Fury is a healthy, well-mannered Standardbred trotter. He's calm, reasonable & an easy keeper. He stands perfectly for vet, blacksmith and grooming and is easy to load on/off trailer. I do not ride so I have not tried him under saddle, but like m ... Read More